text:
What is ADS-B and who needs it?
I read that ADS-B is required by the year 2020. What does this mean? What is ADS-B used for, and who needs it?

To answer your first question, ADS-B stands for Automatic Dependent Surveillance - Broadcast.

Automatic in the sense that it operates without external stimulus (unlike radar)
Dependent in the sense that the surveillance information is derived from on board systems
Surveillance in the sense that it's primary intended to provide surveillance information to other parties
Broadcast because it transmits to all listeners without knowing who those listeners are, there is no two-way communication.

The capability of an aircraft to transmit ADS-B signals is called ADS-B OUT, the capability of an aircraft to receive ADS-B signals is called ADS-B IN.
ADS-B data contains information about the identity, position, altitude and velocity of the aircraft. The position and velocity information is derived from GNSS (GPS).
There are three technologies defined for ADS-B

1090ES is operating on 1090 MHz, the same frequency used for Secondary Surveillance Radar (SSR) and Airborne Collision Avoidance Systems (ACAS/TCAS). Messages are transmitted by the same transponder that also replies to radar interrogations. This will be a Mode-S capable transponder because the data is formatted in a similar way. Since this frequency is the worldwide used standard for aviation, international aviation will use this ADS-B standard.
UAT (Universal Access Transceiver) works on 978 MHz. A special transceiver is required to use this form of ADS-B. The transceiver is able to send and receive data, it will also receive ADS-B transmissions from other aircraft. UAT is only allowed within the USA and China. The frequency 978 MHz is reserved for other purposes (DME/TACAN) in other countries.  To encourage people to equip with ADS-B voluntarily, the FAA provides additional services on UAT. These are Traffic Information Service - Broadcast (TIS-B) which transmits position of aircraft detected by FAA's SSR's and Flight Information Service - Broadcast (FIS-B) which provides the receiver with weather information and operational data such a airspace restrictions and NOTAMS.
VHF Datalink Mode 4 (VLDm4) uses a frequency in the 118-136.975 MHz block, which is internationally reserved for aviation. Normally these frequencies are used for voice communications, so a special radio is required to support VDLm4. Just like UAT, VDL mode 4 allows for services like TIS-B and FIS-B. VDLm4 was tried in Sweden and Russia, but has not been able to gather much mass. It is unlikely that it will be used on a large scale.

Since you mention 2020 as the year by which aircraft should be equipped with ADS-B I am going to assume you are from FAA-land.
The FAA mandates aircraft in the 48 contiguous states (and D.C.) that operate in class A, B, or C airspace or class E airspace above 10000ft (class E airspace below 2500 AGL excluded) to be ADS-B OUT equipped by January 1st, 2020.
The mandate itself can be found here and the associated Advisory Circular (AC90-114) can be found here.
Aircraft operating below 18000 ft can use either UAT or 1090ES. Above 18000ft, 1090ES is to only approved ADS-B technology.

Countries that have ADS-B mandates are (this list is probably not exhaustive)

Australia
Canada
(Hudson bay)
China
Countries in the European Union
Fiji
Hong Kong
India
Indonesia
Seychelles
Singapore
USA
Vietnam

I believe that the EU is requiring this next year isn't it?

@Lnafziger yes, but not for all aircraft. Politics and lobbying have complicated the rule. And it might be even subject to change.

Maybe the reference to the logic behind the terms could be added. I think dependent also means that, for ADS-B concept to function, there should be good-hearted willing-parties that broadcast their location at all times. and i case of a system failure other backup methods (systems or procedures) should be available.

@GürkanÇetin The term cooperative surveillance is used for what you describe. ADS-B is a form of co-operative surveillance, just as secondary radar and multilateration.

I don't believe Canada is mandating ADS-B. The most recent information I could find is from 2011-03-11 https://www.tc.gc.ca/eng/civilaviation/opssvs/managementservices-referencecentre-acs-700-700-009-130.htm#s3_0 saying that it isn't being mandated

@mark, ADS-B is mandated for operations over the Hudson bay.

ADS-B is a complex topic, but the FAA has mandated that by 2020 most aircraft operating in any airspace that currently requires a Mode C transponder should be "ADS-B Out" equipped, with minor exceptions.
Notice that it is possible to be "ADS-B In" equipped but not "ADS-B Out" equipped.  The FAA does not mandate anything regarding "ADS-B In" yet.
There are various safety and efficiency benefits of having ADS-B equipped aircraft.  ATC benefits from ADS-B Out by having more accurate position information, allowing them to potentially allow aircraft to operate closer to each other since current radar technology is far less accurate.  Pilots benefit from ADS-B In by being able to receive weather in the cockpit and see the depicted positions of aircraft around them for collision avoidance.

This MIT paper is a bit dated, but very technical information about the ADS-B protocol for the tinkerer in you.


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How is the cargo hold volume for passenger aircraft designed?
An A380 has up to 2 decks for passengers and only 1 deck for cargo (for passenger's luggage), whereas a B777 has 1 deck for passengers and 1 deck for luggages. It looks like the volume of luggage per passenger is reduced in a A380 compared to a B777. Is that true? Is the volume of luggage per passenger the same? Is there a method to calculate the volume of the cargo and then to design its shape?

The cargo hold volume is a secondary result of the design process. Pressurized fuselages need to be round for best structural efficiency, and the passenger compartment needs to be high enough for passengers to stand upright. The rest has to follow from that, and the old narrow-body aircraft (like the DC-8 or the Boeing 707) were mostly volume-limited (which means that they would have benefited from more internal volume), whereas the early wide-bodied aircraft (A300, Boeing 747) are weight-limited (which means operators flew them with some volume unfilled to avoid overloading the plane).

The picture shows the fuselage cross section of an A310 (left) and a Boeing 737 (right), which are typical for wide-bodied rsp. narrow-bodied designs. Note the relatively bigger freight compartment of the Airbus fuselage.
Even bigger fuselages than those of the Boeing 777 or the MD-11 offer so much internal volume that two passenger decks are needed to avoid flying lots of empty space around. McDonnell-Douglas planned for a while to expand the passenger load of the MD-11 by adding a lower passenger deck forward of the wing, and Airbus did the logical thing and designed the A380 from the outset as a double-decker. Other designs of a similar size came to the same conclusion.
Note that cargo volume on long-range variants of several aircraft is reduced because a fuselage tank had to be added aft of the wing.
In all cases the cargo volume was determined by what was left unfilled.

Next to the Su KR-860 you could also mention the MD-12.

@florisla: Did you check all the links in my post? Several words are links, and sometimes every word points to a different link. The one about the expanding passenger load of the MD-11 points to the Wikipedia article on the MD-12. I wanted to avoid another lengthy post ...

Sorry, I missed that.  Got confused by your statement that the lower deck was forward of the wing; wikipedia mentions that the MD-12 double decks were 'extending the length of the fuselage'.

@florisla: These were different steps of the project. Initially, McD wanted to put a lower deck into a slightly modified MD-11. Did you see the link to the Sukhoi project?

Yes, I saw the link to the Sukhoi, that's why I was tempted to mention the MD-12 ;-)

@florisla: Of course you did, you mentioned it in the first comment. Sorry, I missed that.

The cargo compartments are not only for luggage. Commercial cargo also travel on passenger aircraft, besides cargo aircraft. With luggage alone, there are plenty of spaces in the cargo deck.
In fact, if you fill all the seats, all the cargo space and sufficient fuel for a long trip in a B777, the plane won't takeoff - its GW (Gross Weight) exceeds the MTOW (Max Take-Off Weight).
Airlines are smart people - if a flight is not full, dispatch will put more cargo on the aircraft to utilize it. A lot of passenger airliners also offer air delivery service.
Some passengers complain, "I can't book the flight. The staff says it's full, yet there are many empty seats!" Commercial cargo yields more revenue than an economy seat. Thus, given the weight limitation, an airline may prefer cargo vs passenger.
I don't have info about A380, but I'd guess that the A380 has less extra cargo space than the B777. But as long as it's enough, it isn't a problem.

Also while for passengers 1 deck is 1 deck, cargo can be stacked, so the height matters.

If I understand correctly the response, the volume for passenger's luggage in the cargo hold is only a small part of all cargo volume available, and passenger's aircraft commonly convey commercial cargo not related with passenger transport.

@kayson Please spell out GW and MTOW

@ManuH yes, that's what I'm trying to say.

Cargo compartments in airliners are generally in two categories: regular cargo and bulk cargo. This graphic shows the compartments in a 777.

The normal cargo compartments are generally filled with containers called Unit Load Devices. These are standard containers that can be filled with cargo and easily loaded/unloaded from the cargo compartment. Palletized cargo can also be loaded.

The bulk cargo compartment is for non-containerized cargo like loose luggage. You can see that the majority of cargo space is reserved for non-bulk cargo.
In the case of the A380, there is a large bulk hold as well as plenty of room for other cargo.

...so the bulk hold is an "abnormal" cargo compartment?  :-P

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How many type ratings are pilots allowed to hold at once?
I think i've read that the B787 has a common type rating with the B767 and B777. But I also think I've read that pilots are only allowed to fly two types of aircraft at a time...
So when they go to fly the 787, do they have to give up one of the their ratings if say they were previously allowed to fly the 767 and 777? Would the same still apply for say a B757 and B767 which have very similar flightdecks?
EASA and FAA perspectives would be appreciated :)

There is no limit to the number of type ratings that a person can hold. The world record for most type ratings held by an individual currently stands at 105!
For safety reasons, most airlines only allow a pilot to be currently assigned to two aircraft types at one time so that they don't start to confuse the different airplanes and mix things up. This isn't a regulation though, at least in the US.
In your example, those airplanes are the same type so would only count as one of the two that they could be assigned to, but this will vary based on individual airline policy and the complexity of the differences between the actual aircraft involved.

thanks, that clarifies everything :) on the topic of that world record holder, is there a minimum that must be flown on each type, or is it only overall hours which count?

@Manfred To get a type rating, you just have to complete training and a checkride.  You never even have to fly the airplane!  Another answer of mine shows what is required to obtain a type rating.

wow, that's interesting, thanks :D

It should be noted that being rated and current are two different things. You never lose a rating earned (at least in FAA-land), but that doesn’t mean you’re legal to use it.

It is very impressive to have so many type ratings.  I counted several Bell and Sikorsky helicopter type ratings that could be below 12,500 lbs.  If those were earned today, would not be on the pilot certificate.  Do I think his 105 types are valid?  Yes!  He earned them using the rules at the time.  It may be difficult to beat using current FAA rules though.

There are ICAO countries that will remove a type rating from a pilot certificate when they are no longer current.  Mexico comes to mind.  I am also thinking some EU countries do this as well.

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text:
What is the exact definition of a "crew duty day"?
How do you define a crew duty day? When does it start and when does it end? Also what are the legal limits (in other words how long can a crew duty day last in terms of hours)?.
Edit: Here is a link I found, which basically defines what a Duty period is for the Australian Civil Aviation Safety Authority: https://www.casa.gov.au/standard-page/duty-time-flight-time-and-flight-duty-period.
My question: does each country define its own rules for what constitutes a duty day or do you have standardized set of rules. What happens when you fly say from the US to Australia? Which set of rules prevail?

For which country?

Let's start with the US. I guess Europe has its own set of rules.

You used an airline tag. Should we assume you are asking about scheduled 121 air carrier operations?

From @justin deleted post: See also: Flightcrew Member Duty and Rest Requirements

This question is very broad, even if only asked about one jurisdiction. Answers will depend on which regulation the operation is conducted under, how many crewmembers, local POI interpretation, and company manuals.

@JonathanWalters I am actually asking this in the context of a Fatigue Risk Management System (FRMS). In this case you need to have periods of rest between 2 "crew duty days". I am oversimplifying here, the actual rules are way more complex. Basically I was wondering if you had a common definition of what constitutes a "duty day".

To my knowledge the term "duty day" is not used in 14 CFR 121 or 135, much less defined therein. So my answer to that part of your otherwise broad set of questions is no, the term does not have a legal definition. The air carrier that I work for does not use the term either. The pertinent terms are flight time, duty time, and hours of rest, or rest period. Other carriers may use the term, however.

@JonathanWaltersThanks for your clarifications! If you add your comment as an answer I will accept it!

How do you define a crew duty day? When does it start and when does it end?

In the most simplistic terms, a crew's duty day can be defined in two parts: the "flight duty period" (FDP) and the "flight time".
The FDP begins when the crew "clocks in" for their shift. There might be administrative duties to accomplish prior to flying, so "flight time" has not yet started. The FDP ends when the last flight that they operate blocks in. The Flight Time begins and ends with each Block Out to Block In, and there might be several individual flights within a single FDP. Once the FDP is over, they might still be required to attend to admin duties, but their FDP "clock" has stopped ticking. Their "rest" clock has not yet started, just because their FDP has ended. (Some of these terms and definitions will be expanded upon later.)

Also what are the legal limits (in other words how long can a crew duty day last in terms of hours)?

This is an extremely complicated question, and the rest of this answer will be devoted to this, in conjunction with your other sub-questions.

[Are there] standardized set of rules?

Not necessarily rules, per se... but the ICAO does have a lot of documentation about duty/rest, fatigue management, and the effects on safety. Although the ICAO cannot publish laws, most of it's member nations write their aviation laws in close conjunction with ICAO's recommendations. These nations have ratified treaties stating that they will "abide by" most of the ICAO's recommendations.

does each country define its own rules?

Yes, each regulatory body has its own laws for determining duty/rest requirements. Most are very similar, and based on the ICAO's body of documentation and research.
Narrowing this down even further, each carrier develops it's own policies and procedures that are based on (and approved by) it's parent nation's regulatory body.

What happens when you fly say from the US to Australia? Which set of
  rules prevail?

You will follow the policies of your air carrier, which are enforced by your carrier's country of registration.

Let's start with the US.

Ok, within the US, most of the rules regarding duty/rest for Part 121 Air Carriers are enumerated in Part 117: Flight and Duty Time limitations and Rest Requirements: Flightcrew Members.
There are some "All Cargo" duty/rest requirements under Part 121 Subpart Q (Domestic), Subpart R (Flag), and Subpart S (Supplemental); however, carriers can chose to use these 121 Subparts OR Part 117, but not both. Once they make that choice (listed in their GOM/OpSpecs and approved by the FAA), they are stuck with it.

What is the exact definition of a “crew duty day”?

As noted in the comments of the question, this is not a legal term within the US FARs. Under Part 117, we find the definition for these related terms:

Calendar day means a 24-hour period from 0000 through 2359 using
Coordinated Universal Time or local time.
Duty means any task that a flightcrew member performs as required by the certificate holder, including but not limited to flight duty period, flight duty, pre- and post-flight duties, administrative work, training, deadhead transportation, aircraft positioning on the ground, aircraft loading, and aircraft servicing.
Flight duty period (FDP) means a period that begins when a flightcrew member is required to report for duty with the intention of conducting a flight, a series of flights, or positioning or ferrying flights, and ends when the aircraft is parked after the last flight and there is no intention for further aircraft movement by the same flightcrew member. A flight duty period includes the duties performed by the flightcrew member on behalf of the certificate holder that occur before a flight segment or between flight segments without a required intervening rest period. Examples of tasks that are part of the flight duty period include deadhead transportation, training conducted in an aircraft or flight simulator, and airport/standby reserve, if the above tasks occur before a flight segment or between flight segments without an intervening required rest period.
Rest period means a continuous period determined prospectively during which the flightcrew member is free from all restraint by the certificate holder, including freedom from present responsibility for work should the occasion arise.

From there, it can get extremely complicated and an airline's crew scheduler probably could not do their job without the aid of a computer. Flight crewmembers are restricted to a certain number of hours in a duty period, and there are limits to cumulative hours as well:

total Flight Time cannot exceed:
-- 100 hours in any 672 consecutive hours or
-- 1,000 hours in any 365 consecutive calendar day period.

And then...

total Flight Duty Period cannot exceed:
60 flight duty period hours in any 168 consecutive hours or
190 flight duty period hours in any 672 consecutive hours.

They are required to have a certain number of hours of "rest" in between these duty periods, and those rest hours are required to be in a certain type of facility (if they are not at home).
The amount of time in the cockpit for a flight is also determined by what time of day you start, whether or not there is an on-board relief crew, whether or not you have crossed more than 60 degrees of longitude (and if you HAVE, how long have you been within the new "theater"), and several other factors.

So, finally, back to your question:
What is a crew's "duty day", and what are the legal limits? The answer is so complicated, that the Air Line Pilot's Association has published a 60-page document (updated several times) with 128 scenario-based Q&As just to help "clear it up".
ALPA's FTDT Limitations and Requirements (May 2015)

Jimmy, many thanks for your detailed information! Your explanations  actually makes things a  lot clearer to me :) I am currently working on a software project and nobody could give me a clear definition of "Crew Duty Day" although they use the word the whole time :)

"your explanation makes things a lot clearer".  Ha! :-) I'm glad you liked the answer, @BigLudinski , but I'm not sure I made anything more clear. This is way too complicated a topic to be made very clear.  However, I suggest taking the time to look through that ALPA document - most of those questions are "what if this? what if that?" scenarios.

I guess in the most simplistic term, a crew's duty day can be defined in two parts: the FDP and the Flight Time.  The FDP begins when the crew "clocks in" for their shift, and stops when they "clock out".  The Flight Time begins and ends with Block Out to Block In. There might be several individual flights within a single FDP.  But the length of both the FDP and the FT(s) are constrained by all of the restrictions within Part 117. (Edit: I think I'll add this to the top of the answer)

FDP doesn't end when the crew "clocks out" -- it ends when the last flight that they operate blocks in. They can still be on duty as far as the airline is concerned (post-flight tasks, a deadhead positioning leg, clearing customs, etc) for some time after this. Those required tasks are part of the "duty day" and that time is most certainly not considered to be rest.  BUT, it isn't part of the FDP.  "Crew duty day" is essentially the time that a pilot is on duty (as defined in your answer), and often contracts limit how long this can be (i.e. deadheading for 24 hours wouldn't be allowed).

Thanks for catching that @RalphJ, that is explicitly stated in the Part 117 definition of FDP.


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FAA Regulations for Passenger Aircraft
Does the FAA have regulations for aircraft that carry passengers over large oceans regarding number of engines and flying range of the aircraft ?

@J.Hougaard: While relevant here, ETOPS is not the full answer. You need to add minimum reserve rules and maximum distance to alternates rules for a full answer.

I really don't agree with the duplicate one (I cast for too broad, but the system uses majority votes), however at the very best this is either unclear or too broad. Please review the FAR's regarding commercial operations and then come back with specific questions.

The FAA has lots of regulations that would apply here: 14 CFR parts 25, 91 and 121 at least, plus whatever is required by the airline's OpSpec (which are approved by the FAA). That means your question is very broad, you'll get a better answer if you can make it more specific and limited.

Definitive answer: yes, it does.  Lots & lots of them.

you could at least mention some, otherwise it does not really help the OP.


text:
Can a "crash landing" be used for FAR 61.57 currency?
FAR 61.57 (a) requires that one must make 3 takeoffs and landings within the preceding 90 days in order to carry passengers.
Does a "crash landing" count for the 61.57 currency? By "crash landing" I mean a landing on which an incident/accident occurs under the NTSB definitions.
For example, if I'm in the circuit to gain 61.57 currency, and on my 3rd landing attempt, I crash the aircraft into a tree well short of the runway. Would I then be allowed to go rent another aircraft and carry a passenger?

In this case you'll definitely have greater problems than your currency. I'm not sure, that's why I don't write an answers,  but in my eyes a crash is some kind of landing - only by definition and without any evaluation. Maybe it can even be used to remain current,  but you might don't even have to worry about your currency after this kind of incident.

@Falk I agree, I just think it's an interesting hypothetical question. Obviously if that happened to me, currency would be the last thing on my mind.

Perhaps a better example (which doesn't immediately call your piloting ability into question) would be if the landing gear folds on touchdown or something?

@roe Really not much difference in the hours following the crash from a legal perspective.  (In your case though, you probably wouldn't get the follow-up-reexamination-letter bit so would be simpler over-all.)

@Lnafziger; true, but using "parking in a tree" as an example seems to have drawn the attention away from the actual question :)

@roe Maybe, but determining fault is tricky, so what about the questions in the middle where the investigation has to determine "fault"?  That takes awhile....  That's why they have the process that they do and don't just suspend your license on the spot!

This is the most awesome question I've ever seen on an aviation Q&A site. Bravo... +1!

Be aware that for night currency, the crash landing must be to a complete stop.

@falstro.  I have folded a landing gear on landing with a subsequent chewing up of prop.  Heavens yes, I logged it as a landing, it being a far more interesting and instructive experience than the majority of my other landings.

Any landing you can walk away from...

If you logged 3 good landings then crashed, yes.  If you logged 2, then hit a tree short of the runway, then no.  See how easy that was?!

As far as I can find, the FAA doesn't define the term landing so it could be argued either way.  The "typical" definition of landing is:

1: an act or process of one that lands; especially :  a going or bringing
to a surface (as land or shore) after a voyage or flight

That definition doesn't say that it has to be "controlled" or that the airplane has to be usable again!  Even if you decide that it wasn't a "successful landing", you could always get your third landing later if you are still allowed to fly, and then carry the passengers.

So this brings us to the second part of your question:  Are you allowed to fly after an accident?
Since you had an accident (as defined by 49 CFR 830) you must immediately notify the NTSB of the accident.  Once you do that, you have 10 days to file the required report.
At this point, you still have a valid pilot license and can legally fly another airplane.
Chances are however, that you will be receiving a certified letter from the local FSDO requiring a reexamination in order to keep your license because your competence has been called into question.  If you don't call them to make an appointment, they will start the process to suspend your certificate.  During this time, you can also continue to fly because you still have a valid license.
The FAA can also use their emergency authority to immediately suspend your license if they feel that it is warranted.  This can be appealed to the NTSB if you feel that it isn't justified, and they have up to five days to respond.  At this point you are not allowed to fly pending the response from the board.

This, and a lot more information can be found on AOPA's FAA Enforcement Webpage.

A §49.709 re-examination would require sufficient evidence of gross incompetency or negligence on the part of the aviator.  The circumstances of the landing would have to be reviewed and may or may not warrant that.  An emergency revocation of an airman certificate would imply an INTENTIONAL act of reckless behavior.


text:
Why are propeller airplanes still made?
Airplanes with propellers were invented a long time ago. After that, jet engines came into existence. My question is: why do we still have propeller engines?
The reasons I can think of are:

They are cheaper;
They cannot achieve very high speed;
They are not very noisy (though not always).

Besides these, are there any other reasons general aviation airplanes built nowadays don't have jet engines?

Ok, so in the non-confused sense: Would you like to know why we're still using propellers (rather than jet propulsion), or still using reciprocating engines (rather than turbine engines)? Or both?

Basically the former one.

Somewhat related question: Rotary-engine planes in commercial flights

The number one fan of a bypass jet turbine engine is a propeller.

Another related question: Why is flight training done in prop planes instead of jets?.

Jet engines are only efficient at high altitudes and high speed (25,000+ feet or so and 300+ knots or so true airspeed).  The cost of making and operating an airplane capable of flying there is very high, and most general aviation flights have no need of such performance (or expense) hence, propeller airplanes.
Reciprocating engine propeller airplanes are relatively efficient at low altitudes and airspeeds, they are more economical for the average types of general aviation flights.  They are also much cheaper to build and operate than a turbine powered airplane.
Turboprops fill the efficiency gap between reciprocating and pure jet engines, being most efficient at mid altitudes and airspeeds.  Still more expense and performance than most general aviation flights need though.

I'll add that if you put a turbine on a C172 the 40 gallons of jet-A in the wings would probably not get you very far.

Good answer! I'd say that the most important aspects though are that they are a) cheaper to build and b) cheaper to operate.

Don't forget the Turbo-fans which bridge the gap between turbo-props and pure jet by using a bit of both :)

Also, piston engines just make more sense until power demand reaches around 500hp

are there any jets still being manufactured with pure jets? I don't think laymen (including OP) knows that he is even flying in a turbofan.

Yes, I know I'm flying a turbofan.  They are rarely referred to as such on the line.

It is all mission related.
Propeller engines - and I am including turboprops - are much more efficient at lower speeds and altitudes.  Example: the C-130 Hercules cargo aircraft.  It can get in and out of fields much shorter than a turbojet or turbofan can, while trucking a large load, because it has those huge propellers clawing at the air.  Jets, as stated before, have the advantage high and fast.  But that is not the mission of the Hercules.

As mentioned they are efficient at lower altitudes (and service the GA mission quite nicely) but in many ways it simply boils down to cost. There are companies out there designing and working on smaller jets like Cirrus with the SF50. Then there are a few jets out there like the Cessna Citation Mustang that are single pilot certified and can be flown with appropriate ratings on a PPL. But the fact remains that it is not cheap nor easy to bring a new airplane to market. Cirrus first flew their jet in 2008 and its still not on the market officially. That puts them at nearly 8 years from prototype to roll out and Im sure the first lines for it were drawn well before 2008.
On the other hand companies like Piper and Cessna have approved designs that are still fast and easy to maintain even by todays standards. Very much the "If it ain't broke don't fix it" issue. It is no mystery that GA sales are down and some of the companies could be doing better.
There is a bit of a safety issue. Propeller planes are nice and easy to fly with fast throttle response and lower speeds they make great trainers. Some may argue that jets are just to much plane to handle for a new pilot.
For what its worth there are some very fast piston singles out there. The Glasair claims a cruise of 252Ktas (although its experimental) and the full production Mooney Acclaim Type S pulls in at 242Ktas both of these planes approach turbo prop speeds to the piston engine while an old design can still deliver performance (and high speeds).
There is also some cross over with automotive piston engines. Through out history there have been a few auto engines certified for aircraft. Once upon a time Ford had some motors that found their way into planes. Mooney has attempted to use car motors at least twice starting with the Crosley engine that was found in early Mites and culminating with the epic (if you are a Porsche fan like me) PFM3200 that featured the Porsche 3.2 engine out of the late 80's Carrera. While the PFM3200 was riddled with issues and Porsche eventually dropped the FAA certification for the motor it was an interesting display of engineering. Parts for the 3.2 were arguably easier to come buy and there were plenty of people who knew how to work on them. Currently Diamond offers a diesel DA42 that runs on modified car motors. Again using a motor that is tried and true on the road. So the costs are not just because the engines are cheaper to make but made in much higher quantities as well as being able to offset some of the engineering costs with this bulk.

The cruise speed for the Mooney Acclaim Type S is 242Ktas not 424.

@TeasingDart good catch, I have updated.

Re "fast piston singles", I think you're overlooking the fact that a lot of us who fly single-engine prop planes aren't looking for fast.  We might instead want to get in and out of short dirt strips (or no strips), do aerobatics, take a leisurely sightseeing flight...

Piston-driven propeller powerplants are:

Cheaper. Because the engine is a proven and well-understood design, they're cheaper to design, to make, and to maintain, all of which lower expenses for the pilot. You can pick up an older Piper Cherokee for about \$40k nicely equipped with plenty of hours before its next overhaul. The absolute cheapest Piper turboprop I can find with a quick search is a twin-engine Cheyenne for \$275,000, and it probably needs work as they average closer to \$400k. Other turboprop airframes approach $2 million a pop.
Smaller. A four-cylinder air-cooled naturally-aspirated piston engine is not much bigger than the V-twin on a motorcycle. Smaller tends to equal lighter, and it also allows for more cabin room in a fuselage of the same total volume, and less variance of the CG with cabin weight (which is a big deal in small planes).
Simpler. There's not as much to go wrong with a fixed-pitch air-cooled piston-engine plane. This again reduces maintenance costs but also increases safety by lengthening "mean time between failures" that would require emergency procedures. Constant-speed props are a little more mechanically complex but not too bad. Turboprops a little more complex still.
Better-performing at low altitudes. Most turbofans are designed for operation above 10,000 feet, while most propeller-driven craft are designed to fly at 8,000 or below because their cabin is unpressurized. At lower altitudes where the air is thicker, piston engines run more efficiently and cooler than turbofans and much better than pure jets.

You're comparing small piston engines with small turbines. Turbine engines are well understood, simple, and light with a higher power/weight ratio than piston engines. Only for small engines are pistons still an option due to small turbines not being very efficient. But the question was about propellers.

At the size of aircraft where propellers are most common, so are reciprocating (piston) engines. Efficiency in smaller engine sizes is a concern, and so is cost; small single turboprops start about three times the cost of small single pistons, brand new off the factory line, and well-maintained turboprops hold more value partially due to lower used supply.

Ultra-light jets were all the craze a decade ago, and never took off: they were too fuel inefficient. Propellers do a much better job at converting fuel chemical energy into thrust that propels the aeroplane forward, than jets do.
Aerodynamic thrust can be written as $T = \dot{m} \cdot \Delta V$, with $\dot{m}$ the mass stream of air in kg/s and $\Delta V$ the speed increase of the propelled air mass in m/s. To get the highest propulsive efficiency, accelerate the largest amount of air to the smallest $\Delta V$. Propellers have a much higher effective disk area than pure jet engines do, and deliver way more thrust per installed engine power than pure jets do.
The turbofan is much more fuel efficient than a pure jet because the large bypass fan works kind of like a propeller does. However, the turbofan is still less efficient than a turboprop, simply because of the larger blade radius.
The issue of piston engine vs turbine engine for general aviation is a separate one altogether. Piston engines are heavier but have better fuel economy. Weight-wise they scale up very poorly, while this is where the turbines fully come into their own: nothing beats a large turbine in power/weight ratio. Smaller turbines are not very efficient due to lower pressure ratios from blade/shroud gaps.

It's very simple: Prop planes are manufactured because most airports around the world have runways too short for jets.

How big a runway do you think you'd need for a small GA aircraft with a big jet engine...?


text:
On a larger airplane, how do they manage balance?
I have flown a bunch of times on a Bombardier Dash-8 Q400 on a couple of different airlines, and several times I have flown a shuttle flight that is basically empty.
I have been instructed to change seats on these flights, reportadly to balance the plane better.
It appears as though the request comes from the cockpit relayed back to the cabin staff.
The plane appears to be static in place, so how do they determine that they need to balance the plane?  Does the landing gear report this sort of info?
A Dash-8 is a reasonably 'large' airplane that it seems sort of surprising that the balance is so delicate that the weight of a few people can make the difference.

Back in to mid-80s I was a first officer flying Metroliners for a commuter airline. If there were few passengers, they had to be seated aft of the wing mid-point or your c.g. would exceed the aft limit. It was the job of the first officer to stand at the cockpit entrance, just forward of the entry door, and tell passengers where to sit when there was a light load. A very large African American came up the steps, and I had to tell him to go to the back of the airplane. Realizing what I had said, I hurriedly explained way. I recognized the man, he was Rosey Grier. Google him if necessary.

In the late 80s I was flying F-27 with no autopilots. We had a captain who weighed in excess of 250 lbs. He was a prankster, and when he was deadheading, he never failed at some point in the flight to make three or four circuits of the cabin. You always knew when he was doing it; the airplane just wouldn't stay in trim.

Before the main cabin door is closed, the ramp personnel will deliver a cargo sheet that lists

number of checked bags
number of gate checked bags
number of heavy checked bags
pounds of commercial cargo
pounds of company cargo

With numbers broken down by cargo bin where accurate.
The flight attendant will deliver a sheet with passenger count in zones.
The FMS or EICAS screens can tell you how much fuel is on board.
From there, some airline have ACARS programs that you plug those numbers into and it will give you weight information (to turn #bags and #people into pounds). Other have worksheets to calculate the weights.  In the EMB-145 we then had to spin a special wheel with the weight information to get the balance info.  This can vary by operator.
Some operators will have the W&B calculated by dispatch and all of the numbers I mention above are put into the computer system by various people and the dispatcher will deliver the W&B and takeoff reference data to the pilots via ACARS.
What if there is a problem?
Problems can be overweight overall, overweight in the cabin, overweight in the bag compartments or out of balance.
For overweight, remove people or bags as necessary.  If fuel has not arrived and you can do without some, call dispatch to revise the numbers and load less fuel.
If you are out of balance, you move people or bags around.  This was rarely an issue and if it does happen you just ask a passenger from zone X to sit in zone Y for takeoff.


text:
What button is this pilot pressing with his thumb?
In this video (marker 4:23), what button is the pilot thumbing on the yoke?

It's the elevator trim control to relieve control forces in pitch.  It does this by changing the neutral position of the elevators so that the pilot flying does not need to maintain a constant pressure on the yoke to maintain pitch.  On the 747 family, this is achieved by moving the stabiliser.
Although this image shows a home cockpit yoke, the representation of the controls is accurate:

To be clear, in most large aircraft (maybe all?), the stabilizer is what is moved when trimming.

@Terry Thanks, good point.  I'll edit that in.


text:
Do flight tracking websites also track non-commercial and defense aircraft?
Many flight tracking websites have the data about almost all the commercial airplanes in air. Do they have the data about the private jets and/or defense aircraft also and they just don't show that on the websites?

As long as an aircraft transmits (unencrypted) ADS-B information, anyone within radio range can track it. The equipment necessary to receive ADS-B can be as simple as a computer with a TV receiver (USB DVB-T module) and the right software.
Receivers can then send the data stream to, for example, Flightradar24, who will display it on their website.
As Flightradar24 states, not all aircraft are equipped with an ADS-B transponder, and even those that do may not have switched it on. Unless ADS-B is installed and operating, it would not be visible.
@ezra-g mentiones that Steve Jobs' aircraft was blocked, but this is of something one would have to ask for, and the site has to apply the filter so it doesn't display on its website. However, Jobs' plane would still have been visible on the receiving computers. And, of course, the website will only filter your aircraft if they are willing to do so, either on request, through payment, or a government order.
Flightradar.com also has some other data sources, like FAA (Federal Aviation Administration) radar information in the US, which also contains aircraft without a transponder. The FAA may also filter some aircraft.

And the FAA puts a 5 minute delay on the information

Flightradar24 is not a good example as they filter out military traffic

Any aircraft owner can make a request to the FAA which removes their information from the public data feed.  If they do this, and have no ADS-B (as you say above), then they cannot be tracked by sites like this.

ADSBExchange does not filter flights, even military ones. Their coverage isn't as good, though.

From the FlightAware FAQ:

How does FlightAware handle flights around the world? What is FlightAware's service area?
FlightAware's primary service area includes airspace operated by the United States (including Alaska, Hawaii, Puerto RIco, and Guam), Canada, the Caribbean, Australia, the United Kingdom, and France. Flights in the primary service area support real time maps, departure and arrival information, delays, and more.
FlightAware's secondary service covers scheduled major airline operations at any airport in the world. Flights in the secondary service area support departure and arrival information. Secondary coverage areas may have real-time positions for ADS-B equipped aircraft operating in FlightAware's ADS-B coverage area. Additionally, some airlines send FlightAware satellite position reports from aircraft worldwide that augments other position data and provides transoceanic coverage as well.
For flights arriving in a service area from outside of a service area, FlightAware will be able to track the flight when it nears a service area. For flights departing a service area, FlightAware will be able to track the flight until it leaves the coverage area. Flights may not be tracked beyond that point unless they enter another service area.
Not all worldwide data sources (e.g., European data, datalink ARINC/SITA ACARS, etc) are freely available on FlightAware.com due to government regulations or commercial arrangements. You can contact us if you have a commercial need for worldwide data.

Flight-tracking sites can track military aircraft, but generally don't.  For example, I live near a USAF base and can easily track dozens of military flights a day with an ADS-B receiver, but not one of those flights has ever shown up on FlightRadar24.

What type of AF aircraft are you tracking with an ADS-B receiver? I'm curious which airframes have them now.

@RhinoDriver, Mostly various flavors of cargo planes and cargo plane derivatives, such as the KC-135.  A few oddballs like a U-2S or an E-6A.

Flight tracking websites, such as FlightRadar24 and FlightAware, generally track aircraft using publicly available ADS-B transponder information. Privately operated aircraft are included as long as the owner of the aircraft has not specifically requested that their aircraft be excluded from public searching. For example: Steve Jobs' private plane's N-number was public information, but it was excluded from tracking on Flightaware.
Military aircraft are not included in public ADS-B tracking information.
For more on ADS-B and flight tracking, see the information from FlightRadar24 and FlightAware.

FlightAware also shows non-ADS-B traffic that has a filed flight plan.  So, GA traffic with flight plans shows up, but GA traffic without a flight plan does not show up.

Yes, recently PlaneFlightTracker provided exactly this live service both for NATO and Russian Military aircraft as well as Medical, Emergency, Safe and Rescue helicopters and airplanes. It starts with a procedure explaning how to track as well as Live Military Aircraft Maps. This site uses the FlightRadar24 map for embedment but has made an effort to extract necessary ICAO codes so that the users may get the proper maps.

PlaneFlightTracker is using the Flightradar24 API and thus do not track a number of blocked aircraft. They are basing their "Military" designation purely on the ICAO Aircraft Type Designation.


text:
What is the maximum crosswind component for large airliners?
For smaller aircraft like Cessnas, the demonstrated crosswind component is something like 12 knots but they can land up to 20 to 25 knots. For bigger jets, such as the Boeing 737 and 777, what is the maximum crosswind component?

“Jumbo jet” usually means 747 specifically, not just any large jet.

This link says 38 knots for the 777.
This link says 25 knots for the 777 autoland system.
This site says for the:

737-200, crosswind limit is 31 knots;
for the 737-300 thru -500, 35 knots;
for the 737-600 thru -900, 36 knots; and
for the 737-600 thru -900 with winglets, 33 knots.

From this site:

During the type certification process, the FAA requires the manufacturer to demonstrate that its airplane can be controlled in 90° crosswinds up to 20% of VS0.


text:
Which gas is used to fill the evacuation slides of modern aircraft?
We have seen that after an emergency landing when the airplane needs to be evacuated promptly, evacuation slides get deployed immediately. I am not sure if normal air is being inflated in those slides or do they use some other gas in them?

They are filled with carbon dioxide, oxygen and nitrogen. See here for reference.
From the linked article:

Slides inflate with an initial boost from a canister of compressed
  carbon dioxide and nitrogen. The canister provides only about
  one-third the volume needed to inflate the slides. The remaining
  volume is supplied by ambient air, channeled into the slides through
  aspirators.
When the inflation mechanism is triggered—by a lanyard pulled by the
  slide as it tumbles from its storage case—gas from the canister
  accelerates through the aspirators at high speed, creating a vacuum
  that sucks ambient air into the aspirators through louvers. When the
  slide is fully inflated, the louvers close.

In other words, they're filled with air.

@GdD: Mostly, but the initial compressed gas which provides the energy for filling is not air, but an oxygen-free mixture of carbon dioxide and nitrogen.

The way ambient air gets sucked in by the compressed gas flow is called ventrui effect.

@JustinKiang ... almost: It's called Venturi effect, after Giovanni Battista Venturi.


text:
Do the cabin announcements follow a common protocol?
Until recently, my local airline made all their pre-flight and pre-landing announcements in Swedish and using an informal language. A few months ago they changed this and are now using all the standard phrases (Cabin crew ten minutes to landing, Arm slides, cross check and report, etc.)
Is such a change dictated by some authority or is it the choice of the company? Are the actual phrases defined somewhere, or is it convention?

I can only speak for carriers following FAA regulations. But, It was probably a company policy change. I have a copy of the 2017 FAR/AIM. I don’t remember there being a change since then.
One reason for an air carrier, whether large or small, to use a standard format and phrases is to make sure that every flight and cabin crew completes all of the required elements of a briefing without forgetting items. In the litigious sense, this sort of scripting is much more defendable than simply requiring the crew to mention the required information in their own way.
757toga has listed that guidelines are spelled out in AC 121-24C for US carriers. I would like to also include the locations of the regulations spelling out the requirements for passenger briefings. Other than the required information content contained in the regulations (FAR), and the guidelines in the Advisory Circular and other FAA publications, there is no further guidance on how the briefing is to be delivered. The regulations are in the following Title 14 CFR parts:

91.519
121.571
135.117

Each has a version of the verbiage included below.
In addition to this, the FAA requires all aircraft PICs brief (or ensure briefings are done with all passengers) the operation of safety/seat belts per Part 91.107. The FAA Safety Team recommends following the S.A.F.E.T.Y. format when Part 91 General Aviation aircraft PICs brief their passengers. The acronym stands for the following:

Seatbelts
Airvents & windows
Fire Extinguishers
Exits, Emergencies, & Equipment
Traffic & Talking
Your Questions

This example guidance can be printed out at FAAST SAFETY Briefing
The example verbiage of the actual regulations is below:

§91.519 Passenger briefing.
  (a) Before each takeoff the pilot in command of an airplane carrying passengers shall ensure that all passengers have been orally briefed on—
(1) Smoking. Each passenger shall be briefed on when, where, and under what conditions smoking is prohibited. This briefing shall include a statement, as appropriate, that the Federal Aviation Regulations require passenger compliance with lighted passenger information signs and no smoking placards, prohibit smoking in the lavatories, and require compliance with crewmember instructions with regard to these items;
(2) Use of safety belts and shoulder harnesses. Each passenger shall be briefed on when, where, and under what conditions it is necessary to have his or her safety belt and, if installed, his or her shoulder harness fastened about him or her. The briefing shall include a statement, as appropriate, that Federal Aviation Regulations require passenger compliance with the lighted passenger sign and/or crewmember instructions with regard to these items;
(3) Location and means for opening the passenger entry door and emergency exits;
(4) Location of survival equipment;
(5) Ditching procedures and the use of flotation equipment required under §91.509 for a flight over water; and
(6) The normal and emergency use of oxygen equipment installed on the airplane.
(b) The oral briefing required by paragraph (a) of this section shall be given by the pilot in command or a member of the crew, but need not be given when the pilot in command determines that the passengers are familiar with the contents of the briefing. It may be supplemented by printed cards for the use of each passenger containing—
(1) A diagram of, and methods of operating, the emergency exits; and
(2) Other instructions necessary for use of emergency equipment.
(c) Each card used under paragraph (b) must be carried in convenient locations on the airplane for the use of each passenger and must contain information that is pertinent only to the type and model airplane on which it is used.
(d) For operations under subpart K of this part, the passenger briefing requirements of §91.1035 apply, instead of the requirements of paragraphs (a) through (c) of this section.
[Docket No. 18334, 54 FR 34314, Aug. 18, 1989; as amended by Amdt. 91–231, 57 FR 42672, Sept. 15, 1992; Amdt. 91–280, 68 FR 54561, Sept. 17, 2003]

The question asks if the change from an informal delivery of the information to a more rigid, formalized delivery is mandated by regulation or if this was a company policy change. This answer only addresses what is to be covered in pre-flight announcements, not how it should be delivered, or if there are specific phrases that must be used.

@FreeMan - edited to address changes and delivery guidance.

Better, thanks! So the short answer is "No", there are no regulations on precise wording, only the topics to be covered, but "Yes", it's likely that the company mandated standard phrasing for legal purposes. I don't know if they still allow it, but Southwest Airlines is quite famous for their rather entertaining pre-flight announcements...

@FreeMan - About 20° of my flying as a passenger is on SWA. As of last year, they were still doing it their way. But, if you get the same crew leader on different flights, you will notice that they are still scripting. Even if it is a script they wrote themselves. I fly AA 70° of the time. The first few times seeing their briefing video, I really liked it. Then, it became like an old favorite song or commercial to which I could sing along. Now, it’s a tad bit annoying. Time for a reboot. Surely, they could do that occasionally. And no, I will not stop calling you Shirley.


text:
Why does the aileron on this jetliner swing?

The picture I took here is left wing of a jetliner and it shows how the flap works during take off and landing.
In that video is the inboard aileron, and it shows that the inboard aileron is not firmly controlled. It is like it is swinging up and down.
My question is, why does it look like it swings? Is it intended to be so? If yes, why?

All I see is the aileron being actuated as the pilot (or autopilot) flies the approach.

@Jim, in 4:04, it is still swing even just exactly before touch the ground, which in that situation should no more rolling control.

Why not? The pilot flies the aircraft all the way onto the ground and beyond.

Also, at 4:04 the plane is still in the air.  It doesn’t land until closer to 4:16.

If you look carefully, you can also see the ailerons swing up and down in a seemingly "unfirmly controlled" manner.

For an example of the kinds of control inputs made during a landing see this video: https://youtu.be/JhUcNh5_UPE

@Jim, sorry for my mistake. It was not 4:04, but 4:14, less than a second before it touch the ground. So, good to see in 0.54, just a second after it left the gound.

@Jim, see this B747-8 landing. Even after it touch the ground, it is still swing.

@AirCraftLover - The nose is still in the air - the pilot is still flying. Once the nose comes down the pilot puts out the spoilers.   And besides that clearly looks controlled not flapping around in the wind, right?

@ymb1, thank you for your link, especially the first link. I read it so I late to reply your comment.

The flaperon points downwards to function as a flap, and moves up/down to induce rolling moments, which may be necessary to keep the wings horizontal when for instance wind gusts or turbulence are attempting to roll the plane.
So what you see is the roll control to maintain level flight, the outboard ailerons move together with the corresponding flaperons at lower airspeeds, which can be seen in the video as well.

First, is its official name flaperon? I searched over the net before I posted this, I got [here] (https://history.nasa.gov/SP-367/chapt2.htm) that its name is inboard aileron. Sorry if I was wrong.

If we see in 0:54, it began to "swings", just one or two second after it left the ground. Is rolling performed so immediately after it left the ground?

Maybe it is good to see 0:54 just a second after it left the ground it is already "swings", and 4:14, less than a second before it touch the ground it is still "swings".

@AirCraftLover  A flaperon is an aileron whose "neutral" position is lowered below the normal chord line for low speed flight to provide double duty for roll control and additional lift, so it's accurate to call it a flaperon.  They are also called drooping ailerons.  But as far as I know, Boeing just calls them inboard ailerons whether they droop with the flaps or not, although in that case flaperon is a more accurate term.

The movement of the ailerons in landing is to create rolling moments, which compensate for what the side wind gusts are trying to do: roll the aeroplane. The rapid movements are to keep the wings level. All movement is the result of forces (moments when talking about rotations), the ailerons provide rapidly changing opposing moments for whatever the wind is trying to do.

@JohnK, thank you for your explanation. But there is one question from your explanation: It is used for low speed flight to provide double duty for roll control and additional lift control. I bold the low speed as I read here there is mentioned that flaperon is used for high speed control, opposite to your explanation.

@Koyovis, thank you for your supplement comment. I now understand it that it is intended to be so, it is in control.

@AirCraftLover  They are used for high speed roll control when fully up but moving differentially.  Low speed control when drooped and moving differentially.  They are used as ailerons in all flight regimes, whereas the outboard ailerons may be idled at high speeds.  It's just that when flaps come out, they still work as ailerons, but also droop with the flaps.

@JohnK, many thanks. Now I understand.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


text:
What are the approaches to monetize the external cost of climate change impact on aviation
I am a student that is graduating university soon. I have an urgent case and I am asking for help from the aviation involved community that is aware of enviromental impact of aviation.
I have started to work on my first-cycle studies thesis and I am having a hard time understanding the core aim of my topic and what it specifically means.
The thesis is "Approaches to monetize the external cost of climate change impact on aviation".
Can anyone here help me with understanding this topic and giving me some tips and the main  topics/aims of chapters that will be needed.

This question is too broad for a StackExchange site, and likely requires touching on topics brought up in your classes, anyway.

If you don't understand the core aim of your thesis topic, you should probably go talk to the professor who has assigned you this topic.

You should show your current state of research about different taxes and fees and asks for specific part of it. Moreover, I think this question is more suited in economical politics than in aviation expert websites.

This is more economics than aviation, but let's give it a try.
External cost means that an activity imposes cost on a party that is not part of that activity. This activity is in your case climate change. That cost is in your case the burdens of climate change on aviation. Since aviation is part of what is affecting the climate, climate change is not a pure externality. The wording of your thesis topic could be improved in my eyes.
To monetize the external cost is simply a way to measure the cost such that it can be expressed as a monetary value. The cost would be:

More severe weather events which delay flights or cause re-routing.
Flooding of coastal areas which requires the relocation of low lying airfields, aviation businesses and aircraft factories which are located in soon-to-be-flooded areas.
Hotter atmosphere which negatively affects engine efficiency.

I truly appriciate your time and help, Sir. The issue is, that  I was concerned that this was connected to something like emission reducement and decarbonization  projects such as CORSIA and emmision taxation or technological advancements that would compensate the level of emmisions. I understood monetization as: gaining benefits; making the reduction of emmision more efficient; collecting money from taxes and investing them into CO2 reduction projects.

@Georgeb: Indeed, I also first thought this is about letting the aviation industry pay for their part in global warming. But the way the sentence is structured makes that interpretation impossible – except your thesis adviser is a lousy English speaker. You may want to reaffirm the correct interpretation.

Consider developing a hypotheses statement that can be disproven with data?


text:
Help to understand a specific SNOWTAM
My questions are:

According to the article ''H''; what about the other runway/runways when I want to add extra info other runway/runways too; there is just one runway in here?
According  to the article ''J''  it is indicated that critical snowbanks; but it is again just 1 runway I think so.
According to the article ''P'' 15 is the meter of this taxiway snowbank but in which direction is 15 mt.?

I did not fill any SNOWTAM format so; I want to ask in advance..

Reference: ICAO Annex 15, Appendix 2

According to the article ''H''; what about the other runway/runways when I want to add extra info other runway/runways too; there is just one runway in here?

A SNOWTAM is for a single runway, if you want to involve multiple runways, you would release more than one SNOWTAM.

According to the article ''J'' it is indicated that critical snowbanks; but it is again just 1 runway I think so.

Yes, this is just for the runway identified in C).

According to the article ''P'' 15 is the meter of this taxiway snowbank but in which direction is 15 mt.?

This is the distance between snowbanks in meters. There is no direction there as it just identifies a relative distance between two (or more) objects.


text:
Calculating thrust and required propeller size for a given engine power
I am looking to build an Airplane, the weight of Airplane will be around 20 to 25 kg and I am going to use a 70cc motorcycle engine as an Airplane engine.
I want to know how I can calculate the engine thrust. The 70cc engine is an air-cooled, four-stroke, single cylinder, OHC petrol engine generating a maximum power of 5.19Ps at 7500 rpm and a maximum torque of 0.519kgm at 5500 rpm.
So will it work as a plane engine or not, and can you give me any rough idea about how much thrust will it produce and how big propeller do I need for this engine.

Welcome to aviation.SE. You must edit the title to reflect the question. Also consider take a tour as you are a newcomer.

3.8 kW sounds like way too little. Powered hang-gliders normally use 11 kW.

Related if not a dupe: Can an ultralight aircraft fly with a 18hp engine? (it contains information needed to built such aircrafts)

Hint: Pushing double the volume of air at half the speed will require half the energy. This is why high-bypass ratio engines are better. You will have to balance this with weight and other losses that come from having a larger propeller.

@JanHudec his airplane is almost certainly not manned at 25kg. Maybe he wants a drone?

Does weight 20 to 25 kg mean take-off weight—which implies it will be unmanned—or empty weight—which would be something like a hang-glider?

This that follows isn't an accurate calculation, but may be useful as a starting point: let's say the mass of your plane is 23kg. That's a weight of 225 newton. You have to add 830 N for the pilot, so the total weight is 1055 N. Let's assume, also, that the best L/D of your airplane is 9 at 36 km/h = 10 m/s. In a glide, that would mean a sink speed of 10/9 = 1,11 m/s. The implied 'gravitational power' would be 1055 x 1,11 = 1171 watt. That would be the minimum power required for s/l flight at best L/D and for a 100% prop efficiency. In the real world you might need at least three times that power, around 3500 watt.
Now, concerning the relationship between prop size, power, and thrust, at 100% prop efficiency, you may use this formula for the stationary case (airspeed = 0):

(From Wikipedia entry https://en.wikipedia.org/wiki/Disk_loading). Where P is the power in watts, T the thrust in newton, A the disk area of the propeller in sq. meters, and rho the air density in Kg/m3, around 1,22...

I would feel better assuming that the 23kg was the loaded weight of the (presumably unmanned) aircraft. The questioner did not indicate otherwise

That's true, but the calculation can be easily repeated for any mass...


text:
What is the difference between Mechanical Engineer and Aerospace Engineer?
I really want to get into the Aerospace Engineer industry (I want to design the plane's airframe and basically a little bit of everything) but have no idea what to major in for any job.
I'm really thrown off by all these sites which have mechanical engineer and aerospace engineer jobs but they consist of basically the same job description.
Can you please clear this confusion for me?

https://aviation.stackexchange.com/questions/79569/what-is-the-best-major-to-study-for-a-career-in-propulsion-systems-design

I have a BS in mechanical engineering and an MS in Aero-Astro. As an undergrad you learn about the same content. Either degree will qualify you aeronautical engineering jobs. If you want a non-aero job, the mechanical engineering degree might be a bit better.

The difference is that in the business world, titles are meaningless. What one company calls an ME1, another may call an AE3. What really matters is what you know and how does that line up with the job description.

Pick a university and look at the different in curriculums. MEs won't take aerospace vehicle stabilty and control classes, propulsion classes, etc.  Same toolset, different applications.

If you want to work on the landing gear or passenger seats, a mechanical engineering education is the best qualification.
If, however, you want to work on control surfaces or fairings, an aerospace engineering education is better suited.
While both teach similar basics, the aerospace education is much heavier on fluid mechanics and lightweight design. Having studied aerospace engineering in Germany, I was shocked to learn that master students in Aero/Astro at MIT had no idea how to design a screw connection. Therefore, much depends on the country and its ways of teaching. In the US you will get an excellent education in one narrow field at the cost of breadth. In other countries your education might take longer and give you less expertise in one field but will cover the fundamentals much better.
In general, at university you will be taught how to learn. You will learn the basic stuff which will enable you to read special literature and you will learn where and how to locate resources that help you along. This will be the same in both branches and it depends on you to round out your knowledge yourself.
To quote from an earlier answer:
Take the example of Ed Swearingen: He never went to engineering school, but spent years working with airplanes, gradually moving from handling to repair to improving them. In the end, he was a successful self-employed consultant who helped with a number of airplane designs and created some of his own designs, too.
So here is what I propose to do:

Hang out at a local airport (ideally one with lots of hardware passing through the local repair shops).
Don't shy from getting your hands dirty and from asking questions until you are satisfied with the answer.
Try to find experienced engineers and work closely with them.

Do that for 10 years and you will be hard to beat as an aircraft designer. If you happen to attend University in Germany, be sure to become a member of one of their Akafliegs - that is the best start into an aviation engineering education.
It also helps to build and fly model airplanes. Models can give you valuable lessons in aerodynamics and flight mechanics.

If I dont have a local airport is their a book or a collection where I could lear all this?

"In general, at university you will be taught how to learn." No truer words!  I learned how to find knowledge.  That is my key takeaway from school.

@TimBob: Better ask for a full library. All good books are specializing on some aspect. See what others are quoting from. If a book is referenced often, it is worth reading.

@PeterKämpf Aerospace engineer exist?I allways think exist only aeronautical or astronautical engineer.What is your title?

@member2017 My title: Diplom-Ingenieur für Luft- und Raumfahrttechnik. Aerospace engineering might be specialized in Aero and Asto at some universities, but other universities keep both together as one subject.

@PeterKämpf Braunschweig university keep both branches in one name "aerospace engineering"?Your study include spacecraft,aircraft,missile,rocket,propulsion systems etc?

@PeterKämpf . Aerospace engineering might be specialized in Aero and Asto at some universities 99%  states  dont has own aviation industry,spacecraft they can only dream.I think this is reason why lots of smaller university dont offer astronautics..

@member2017 If we round the number of states worldwide to 200 and then look at the fraction who can and do build aircraft, this is maybe 20%. Spacecraft are built in nearly 10%. More operate them – maybe you don't know all of them. If you look at who operates aircraft, states with their own aviation industries are near 80%. So I cannot follow your last statement.

@PeterKämpf Is better study aerospace engineering or mechanical engineering/ course aerospace?

@user628075 Did you read the first two sentences? If yes, what is your question? Those sentences are my answer and I can only repeat them.

The simple answer is a mechanical engineer designs and builds mechanical systems where is an aerospace engineer will design aircraft and spacecraft and their associated systems. You don’t necessarily need to be an aerospace engineer to enter the business, but it does help I am a mechanical engineer by training and spent a solid 15 years of my life in aerospace engineering.
What I would probably strongly recommend would be pursue an education and a degree that you want to because you won’t be using 90% of it when you go to work. As the choice of school? You can go to one of the big aerospace schools such as Purdue, MIT, University of Michigan, Georgia Tech, etc. and it can be of some help. Then again so can a no name school.  When I worked for Boeing I saw both no-name universities right next to guys who went to Harvard out in the cube farms.
The stuff that most of these firms care about as far as hiring you goes is more proprietary knowledge and software use. If you want to design structures, learn CATIA and NASTRAN.  You’re also going to want to learn a PLM software system such as in ENOVIA or WindChill.  Another big help to get in the aerospace and a lot of their lucrative jobs would be to take a route through the military as an officer.  This can get you both a security clearance, which pays big bucks in the civilian world, as well as access to elite training such as test pilot schools, and that can really help your career.


text:
When to turn on deice boots?

This video says (at 25:06) that you should do it as soon as possible.
but I just learned in class that you should wait for an ice build up then turn it on vs just turning it on. This would prevent an ice bridge to form:

But in the clip it says modern de-ice boots don't have the problem mentioned in the picture.

Sorry I meant to go to 25:26. It talks about bridging over the deice boot and how it can be dangerous. in class we learned to wait for a ice build up then turn it on vs just turning it on.
here is the example. but in the clip it says modern deice boots don't have the problem mentioned in the picture.
http://lessonslearned.faa.gov/Comair3272/deicing_still.jpg

@TangoIndiaMike Explain all that and some more in the question :)


text:
What is the difference between CAN and ARINC?
I want to know the difference between CAN and ARINC, I'm confused about their usage.
For example, the communication between the cockpit and the controllers is done using ARINC protocols. And the data transmitted by probes to the controllers goes over CAN. Why use a different protocol in each case? When is each protocol used?

the communication between the cockpit and the controllers is done by using Arinc protocols. And the data transmitted by probes to the controllers is done by CAN.

That depends very much on the aircraft type.

And when can we use each one of them (Arinc and CAN)

When you design your own aircraft you get to choose.

CAN stands for Controller Area Network. CAN is a bus standard designed to allow microcontrollers and devices to communicate with each other in applications without a host computer. It has its origins in the automotive industry.
ARINC stands for Aeronautical Radio, Incorporated. ARINC is an organisation that amongst other activities produces technical standards for avionics and provides services to aircraft operators.
Amongst the ARINC standards there are a number addressing data communications between avionics components. Most widely used is the ARINC 429 standard which describes an avionics data bus. ARINC 429 allows a single transmitter to communicate data to up to 20 receivers over a single bus.
Comparing CAN bus to ARINC 429:

Cable

CAN: STP or UPT, possible to implement on fiberoptic cable
ARINC 429: STP

Speed

CAN: 1 Mbit/s (high speed) / 125 Kbit/s (low speed)
ARINC 429 100Kbit/s (high speed) / 10-14 Kbit/s (low speed)

Directionality

CAN: bi-directional, connected units can send and receive on the same cable.
ARINC 429: uni-directional, a unit either transmits or receives from a cable.

Number of units on a single bus

CAN: unlimited, although in practice no more than about 32 units will be sharing a bus to avoid data collisions.
ARINC 429: one transmitter can serve at most 20 receiving units on a single cable.

Since ARINC 429 has only a single transmitter, timely data arrival is guaranteed, while CAN has to incorporate transmission collision detection & correction which incurs non deterministic time overhead.
On the other hand, ARINC 429 only uses a parity bit for bit level error detection whilst CAN allows for various methods including CRC checks
Some of this data is obtained from an article on CAN bus in avionics magazine.
Newer ARINC busses like 629 or 664 (AFDX) allow for higher speeds and bi-directional communication. These may eventually replace ARINC 429 (but never underestimate how slow progress in aviation is)

And what about the robustness of ARINC and CAN buses?

Since ARINC 429 has only a single transmitter, timely data arrival is guaranteed, while CAN has to incorporate transmission collision detection & correction which incurs non deterministic time overhead. On the other hand, ARINC 429 only uses a parity bit for bit level error detection whilst CAN allows for various methods including CRC checks.

It's all about fitting the tool to the job.  A Boeing 787 incorporates ARINC 664 for the main network with some subsystems on ARINC 429 and a number of sensors and cockpit controls on CAN (ARINC 825).  Almost all the switches on the B787 overhead panel go through a couple CAN busses, eliminating dozens of wire runs.  There's also a significant difference in cost.

Why do people sometime choose CAN over ARINC629 or vice-verca? It seems to me like they are equivalent

There are many data communication network standards used in modern aircraft. Each one has its own technical specification and cost implication. You may like to research the following Data Communication systems:

ARINC 429 : Single Tx, multiple Rx (20 max) with bandwidth limitations (12.5 Kbps or 100 Kbps). This is both an electrical standard and a protocol standard. Uses 4 byte data words, 19 bits are data.
ARINC 629 : Used on the 777, it increased speed over 429 (2 Mbps) and increase the receiver count to 120. It works on half duplex, allowing single interface to send and receive data.
ARINC 664 / AFDX : Developed by Airbus, Avionics Full-Duplex Switched Ethernet is used on newer aircraft like A380. Can use commercial off the shelf hardware.
CAN bus - also used in A380. Originally developed for the automotive industry

Welcome to aviation.se! Interesting answer -- can you provide links to the various busses you mention as a starting point for the research you've recommended?

You could add MIL-STD-1553 for military aircraft as an avionics bus.


text:
How to know if an airport has PAPI lights?
Is there any way to identify whether an airport has PAPI lights (2-light or 4 light system, doesn't matter)?
I am working on some map generation and using aerial images to identify PAPI lights for airports. I was wondering if there is any quicker way to identify visual whether PAPI lights exisit on airport runways.

Whether an airport has PAPI lights or not is indicated on the approach charts. For instance on this chart, there is a schematic of the airport at the bottom of page 3 that shows you where the PAPI is on the airfield.
If you are looking for airports in France, you can find all visual approach charts on the government website.
Otherwise, this wiki has various links to approach chart ressources.
Edit: If there is not indication concerning the location of the PAPI on the approach chart, you can refer to page 40 of this FAA document concerning visual aids. The schematic here describes the standard location of the PAPI relatively to the strip.

yeah but does an approach chart always tell you where the papi light is on the diagrams? I have Jeppesen charts which tells me that there is PAPI, but doesn't tell me where it is actually placed (roughly) on the runways.

@hagubear The PAPI is (based on the ICAO standard) 15 meters from the runway edge. Most often, it is on the left side, but may be placed on the right for practical purposes. Since it indicates an approach path, it must coincide with the glide slope, so the PAPI isn't very far from where the wheels should touch the ground. Keeping these things in mind, you should be able to easily find the PAPI even if its exact location isn't on the map.

Since you already mentioned FlightGear; they also have the data file from which they generate the basic airport layouts. That should contain the information too.

@usernumber It's more accurate to say "The PAPI (or any other VGSI) must coincide with A glidepath" - it doesn't always match the ILS or GPS glidepath, and when it doesn't the approach plates will warn you about that.

For airports in the USA, I'd look in the Chart Supplement (formerly known as the Airport/Facility Directory). It lists characteristics of each runway, including lighting. Here's one for KEAU, where I did my primary flight training:
RWY 22: MALSR. PAPI(P4L)—GA 3.0º TCH 50´. 0.6% down.

Note that this runway has a 4-light PAPI on the left side of the runway. From the legend:
P4L 4–identical light units placed on left side of runway

I know about the glidescope and localiser readings and they are pretty standard globally (50' TDZ, 3-3.6 DEG glideslope). I was interested in knowing visually where the PAPIs are i.e. on the chart when they show various things on an airfield, do they show where the PAPIs are.

For many airports, the A/FD has a chart. That shows the PAPI locations, if any.

Good answer, was going to mention it, just one thing, the FAA has renamed the A/FD resource as the "Chart Supplements".

@KeithS: I didn't know that! Thanks. I'll update. Looks like the link still works.


text:
Why is the compressed air (from engine compressors) taken from High Pressure (HP) stage instead of Low Pressure (LP) stage?
An aircraft that uses Turbofan or Turboprop engines would be taking the compressed air from 3rd stage and 6th stage (varies) and supplying it to the Pressurisation and Air Conditioning Kit (PACK). This air is cooled, filtered, and then supplied to the Fdeck, FWD and AFT cargo zones for temperature control and breathing. If my understanding is correct, PACK is a kind of compressor itself which cools the bleed air for circulation purposes.
Because the engine has got LP and HP stages (i.e compressors), why can't the engine send the LP stage air into PACK just for filtering? Because LP air is surely cool air which I understand still requires filtering. Without knowing further , it surely saves a lot of effort for installing more compressors and therefore, creating a more complex pneumatic system. Has this not been done or is there something I am missing?
KR,

Coming from the compressor section of the engine, the bleed air is sent to the precooler. Even air from the "low" pressure section needs to be cooled before it is sent to the air conditioning system. Here is a precooler from a CitationJet:

The page with that image notes that the bleed air is "hot enough to melt insulation and alter the heat treatment on aluminum alloys." The precooler reduces the temperature of this air and regulates the pressure to the pack system.
When the engine is at low power settings, bleed air is taken from the high pressure section. The engine must run fast enough that this provides enough pressure for the bleed system to operate properly.
Once the engine gets to a higher power setting, the bleed air is taken from the low pressure section. At higher engine speeds, this air still has the pressure required to run the bleed system.
Since the bleed system needs a minimum pressure to operate, compressing the ambient air to this pressure will always add a certain amount of heat.
Here is a diagram of the bleed system, to help visualize what is going on. Note that even after the air goes through the precooler, it is still hot enough to be used for wing anti-ice.

Really, the key here is "Hot enough" air even from the LP stage. Also, the air is used from both LP and HP stage based on the engine thrust power settings. Seems like at higher altitude (>25000 ft), it will be more like LP stage and <= 25000 ft will be HP stage. Thanks a lot for the answer @fooot

Several principles come together here:

The pressurized air does its job similarly to the gases inside your fridge. Compressing a gas heats it up, and expanding it cools it down again.
A heat exchanger can be proportionally smaller if the heat difference between the two media which exchange heat is bigger.
Engines are designed for some air to be bled off.

If you cool the compressed gas, it will become very cool once it expands. If you take air from the HP stages, it will be hotter and need a smaller radiator to remove the same amount of heat compared to less compressed air from the LP stages.  The same holds true when this air is expanded and used for cooling. You can carry away a lot of heat energy by using this very cold, expanded air and can keep the heat exchanger small and light. Again, using less cold air would require a proportionally bigger heat exchanger.
For every compressor stage there is an optimum mass flow at a given rotation speed where it works best. Depending on the operating conditions, performance will be improved if some air is bled off. I know, this is a very general statement, but I just want to get the point across that bleeding off some air is not always hurting performance.


text:
What is the relation between aircraft altitude and ADS-B coverage?
While reading the description of ADS-B given on the FR24 website (ADS-B How it works), I came across this sentence:

The farther away from the receiver an aircraft is flying, the higher it must fly to be covered by the receiver.

What is the relation between height and coverage in this case?

The ADS-B signal used by FR24 is transmitted on 1090 MHz. Signals at that frequency do not follow the curvature of the earth very well. They work best in line of sight. Aircraft far away from the receiver must be at high altitude to be above the horizon.
At 1000ft, the horizon is about 33 nautical mile away. Aircraft further away will be shielded below the horizon. For 40000ft, the horizon is about 220 nautical mile away.

Due to a slight refraction of the signal the practical range is about 15% further.

+1 Great diagram. The only minor change I'd make is to make the 'Invisible' text horizontal (parallel to the dashed line). Currently looks like the annulus is the invisible region.


text:
Is there a 180HP conversion available for a 2011 160HP Cessna 172R with a Garmin G1000?
I've recently purchased a 2011 172R (160HP) with a G1000 on the sellers promise that I can apply a propeller switch and modified air intake STC to get the derated engine back to 180HP. However, the holder of said STC, AirPlains, shows the kit is only applicable to 1996-2004 172Rs without a G1000. Are there any other manufacturers that can apply this conversion on a later-model 172R, or am I stuck with my 160HP?

I can't answer your question, but it looks like the AirPlains kit replaces the tach and ASI. In a G1000 aircraft, that would presumably mean a software change of some kind, and it's likely that Garmin doesn't provide one. I suspect the G1000 is the limiting factor, not the mechanical systems.

Rookie mistake.  Plane sellers will say almost anything to sell a plane.  Never ever take the word of a seller.  Always demand proof for a claim.  Fear not, however, you may be able to get away with a field approval.  Contact your FSDO for insight into what they will require to approve a 337.

It's not the approval that's the big problem @acpilot, its the fact that the kit isn't compatible with the G1000.

@pondlife ahhh that makes so much sense, why didn't I think of that?

Ya @acpilot I'm really lucky I caught it before money changed hands. Still gonna do it because it's a good deal at 160 or 180HP, but lesson learned.

Not a solution, but I looked at this a couple years ago.  I have a 2005 172R G1000 in a flight school and students tend to go to the 180hp planes, so I looked into the upgrade.  I did find that Cessna did a STC for a limited, sequential group of Serial Number 172R G1000's.  I believe they might have been done for Embry Riddle, but not positive.  I actually found this out from FAA when I was calling them about a STC or Field upgrade.  Got to the same point as your e-mail string.
Bottom line - it has been done.  It can be done.
When I called Cessna about the details they did tell me the block of SN's it applied to, but after that they would not share anything.
After looking into this again today, talking to Air Planes (they are very nice, and they would love to be able to sell a kit for this!) and remembering my conversations - I think I'll do some digging again.  I'll post if I find anything
Mark - 191CA

Thank you so much, Mark! Sounds like there's a path as long as you're willing to harass the right people enough, as usual haha. Your answer gives me renewed energy, I'll try and get ahold of Cessna and let you know what I find as well. Thanks!


text:
What are FARs & where can I find them? What is FAR 23, 25, 135, etc?
The FARs (or Federal Aviation Regulations) are the regulations imposed by the FAA on aviation within the United States.
Many questions make reference to FAR 23, or FAR 91 etc. What are each of these? Where can one lookup the text?

See also: Should we allow questions asking for resources?

I don't think this qualifies so much as "asking for resources" - I know a lot of people who get halfway through ground school before realizing that the FAR/AIM is (a) 2 different books glued together, and (b) really just a paper copy of the Code of Federal Regulations that they can look up on their iPrecious for free :)

In the US the "Federal Aviation Regulations" (FARs) is shorthand for referring to Title 14 of the Code of Federal Regulations.
You can browse all sections of FARs at ECFR.Gov.
FAR 23, for example, covers airworthiness standards. § 23.25 regulates weight limits.

In addition to the eCFR version of the FARs (which is kept current with changes in near-real-time as new legislation passes) you can also get bound copies of the FARs (usually with a copy of the AIM tacked on to the back) at pretty much any pilot shop. With the abundance of excellent electronic versions the paper is mostly useful as a 1.5-lb ballast for weight & balance :-)

FARs on the web
There are several sites on the web, but my favorite is the FAA's own Regulatory and Guidance Library at http://rgl.faa.gov/.  If you click the Code of Federal Regulations link on their main page, you can look at current and historical regulations as well as preamble information, links to the dockets, NPRM's, and more.  Just click on "By Part" under the "Current CFR" section, and you can browse through each section. If you then scroll down, you will find the two that you asked about:

Part 23 - AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES

and

Part 91 - GENERAL OPERATING AND FLIGHT RULES

Click the arrow next to each part and it will show links to the full text of each regulation.
Extra Info
The site also includes the following databases:

Advisory Circulars

Draft Advisory Circulars

Airworthiness Directives

AD NPRMs

CARs/CAMs/Aero-Bulletins
Code of Federal Regulations

CFR NPRMs
CFR Final Rules

Equivalent Levels of Safety
Exemptions
Orders/Notices
Parts Manufacturer Approvals
Policy
Regulatory Basis Tool
Special Airworthiness Information Bulletins
Special Conditions
Supplemental Type Certificates
Technical Standard Orders and Index
Type Certificate Data Sheets


text:
Is it true that the pilot and co-pilot are required to eat different meals?
I was watching a documentary about a Lufthansa A380, and they said that the pilot and co-pilot are required to eat different meals; why is that?
Is it a country-specific requirement, or airline-specific?

Airplane!

I read in a book by J.P Otelli that if they eat the same meal, they must wait at least half an hour between both meal. It is made to avoid both pilot to be poisoned by the same meal. I suppose if it is poisonned, 30 minutes is enough to see first signs of intoxication. But I don't know if it is specific to company, or regulation

It is a company specific rule found in the Flight Operations Manual so is airline specific.  There is usually a statement that goes along with it which also says to avoid foods with a higher than typical rate of food poisoning, such as raw fish before and during the Flight.  In the US, the FOM is submitted to, and accepted by the FAA so the procedures become required.

"Whatddya mean I can't have fugu?!"

Although I have no reliable sources to this, I believe that pilots have to eat different meals to avoid food poisoning and therefore becoming sick mid-flight.
As for drinks, it should not matter as long as they drink from a separate bottle / can.
EDIT: According to the article Are Pilots Protected From Contaminated Food?, it is not in FAA's policy for the pilots to eat different meals.
However, the airlines can still choose to make some kind of rule.

Yes, pilots are required to eat different meals on a flight to avoid the risk of pilot incapacitation due to food poisoning. However the FAA and other aviation regulatory bodies haven't set a law to this effect, yet The rule of pilots having different meals in-flight is completely company-specific.
Here are certain incidents and near-misses of pilot food poisoning and you may check Captain Joe's small video on the topic here


text:
I have a European EASA license - what do I need to do to be allowed to fly in the US?
I own a PPL(A) license following JAR-FCL. Recently, this license has been exchanged for a European EASA license.
My training was on a motor glider (TMG), I do not have ratings for SEP, but TMG and Ultralight only.
In Germany I will have to fly a one hour test on an SEP to get the rating (plus about 5h for training).
What do I have to do in the US to get the rating?

From a private pilot's perspective, there are two possible options: a foreign-based license or a 'full' FAA pilot's license.
The first type is defined in 14 CFR 61.75, which starts like this:

§61.75   Private pilot certificate issued on the basis of a foreign
  pilot license.
(a) General. A person who holds a foreign pilot license at the private
  pilot level or higher that was issued by a contracting State to the
  Convention on International Civil Aviation may apply for and be issued
  a U.S. private pilot certificate with the appropriate ratings if the
  foreign pilot license meets the requirements of this section.

You apply to the FAA and they check with Germany (or wherever) that your foreign license is valid. If it is, they'll issue a foreign-based license "with the appropriate ratings" with no flight or theory test of any kind required. That's for VFR only; if you're instrument rated then you also have to do a theory test as well if you want to fly IFR.
That sounds great - and I suppose it is - but there are two big practical concerns. First, any limitations on the foreign license are applied, e.g. if your license is for daytime VFR only then you're still restricted to that, even if a regular FAA license would allow night VFR. And if your foreign license expires or becomes invalid for any reason, the FAA one does too.
Second, you won't have been required to learn anything about US regulations or flying practices. So you might not fly safely or legally because you simply don't know the rules or even what services are available to you as a pilot (FSS, Flight Following, TRSA etc.). One way to handle this is to get some general orientation or introductory training from a US instructor or school, but as a foreigner that will require TSA approval unless you can do it as ground school only (which is not defined as "flight training"). But you might find - as I did - that some instructors will not work with a foreign student at all until they have TSA approval, whether or not it's just ground work.
The other option is to get a normal, full FAA license. You have to pass the same FAA medical, written and flight tests as US pilots to the same standards. You can count your previous flight time towards the required hours but you do need to be able to pass the tests so you will certainly need some instruction. And as a foreigner you will need TSA approval before you can receive any flight training.
The big advantage of getting a full license is that it never expires. If you really want to get one and you have the time and money then you could look into spending a month somewhere suitable in the US (Florida? Arizona?) at a flight school to get it as quickly and cheaply as possible.

I'm currently in exactly the described situation and I really want to highlight what @Pondlife already wrote. If you're license will be accepted and you get an american airman certificate based on it you are legal but the risks to get illegal are huge. They are bunches of differences from flying in Germany or other European countries and you should be awere of them prior piloting an airplane in the US. I wouldn't recommend trying to learn these by reading only but also by some lessons with an instructor. If you do well and feel safe 2 hours of each ground school and flying may be sufficient.

@Falk, that's great advice but it's worth remembering that foreigners cannot receive training of any kind without TSA approval. I tried to get exactly the introductory training you're suggesting and ended up paying $160 to the TSA for a background check.

Oh damn, that's true. I needed to get the TSA approval anyway, so it was no matter for me but in my eyes you should still consider to invest this money instead of risking high fines or even your life.

@Falk Yes, I completely agree. The point is just that foreigners shouldn't forget that TSA approval is required for all training, so if you get a foreign-based license and try to do the right thing by getting some orientation training you will immediately run into the TSA process. But clearly the (relatively) minor investment is worth it. I'll update my answer with something about this.

@BrianKnoblauch Good point, ground school is specifically excluded in 49CFR1552.1(b) and I've edited my answer. However my personal experience has been that instructors won't offer any training at all to foreign students without approval because the consequences of getting it wrong are potentially very severe and therefore it makes more sense to just avoid the issue. Part 141 schools that deal with a lot of foreign students and know all the details might see it differently from independent part 61 CFIs, of course.

I just brought it up since I ran across this while searching for the CFR. I'm an AGI/IGI (not current yet, will be doing that this weekend), but NOT a CFI.  So, I'll only be able to give ground instruction, not flight instruction.  In my case, I only plan on doing instruction for people I know, and it just seems silly to have to do the TSA endorsement/procedure just to help them with written test prep and do a sign-off when I'll be doing nothing resembling actual flight instruction.  :-)